I could be mixed up here, but I have mplayer working perfectly at home in CentOS 4.4, but I just built it here at work for CentOS 5.0 and it doesn't produce any sound.
My h/w: 00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 01) Dell Precision 390 Intel Pentium 4 3.00GHz 2Gb RAM
The sound from Adobe/Macromedia flash player works fine (in seamonkey) - should I be telling mplayer to build for i386 instead of x86_64? I have pulled down all the codecs I could find, so . . .?